Venetian blind



March 7, 1939. F. E. LAWSON 2,149,301 VENETIAN BLIND v Filed May 7, 193 Sheets-Sheet 1 March 7, 1939." 5 LAWSON 2,149,301

vsumnn BLIND Filed May 7, 1937 s Sheets-Shet 2 E 3 FedZiZazmsorz March 7, 1939. FQE. LAWSON M 2,149,301 VENETIAN BLIND Filed May 7, 1937 3 Sheets-Sheet 3 I'll,IIIIIIII'I'IIIIIIII'IIII'IIIIIIIIIIIIIIIII Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE VENETIAN BLIND Fred E. Lawson, St. Louis, Mo.

Application May 7, 1937, Serial No. 141,225

21 Claims. (01. 156-l7) The present invention relates in general to a Venetian blind and is more particularly concerned with the details of construction of such a blind, whereby simplicity of construction is secured and manipulation of the blind is facilitated.

A primary object of the herein described invention is to provide improved means for raising and lowering the blind.-

A further object is to provide in connection with a Venetian blind or the like, an improved mechanism for raising and lowering the same, which is so constructed as to automatically maintain the blind in adjusted position and at the same time enable it to be readily and easily manipulated to raise and lower the blind to other positions of adjustment.

A still further object is to provide an improved Venetian blind raising and lowering mechanism which incorporates a novel worm and worm gear drive, wherebyreverse drive of the mechanism due to the weight of the blind is eliminated.

Another object of the present invention is to provide an improved. housing structure for the elements of the blind operating mechanism,

- which will enable the use of a standard pre formed blank of such construction that it may be utilized for effecting housings which are adapted for either right or left hand mounting, .as desired.

Still another object of the invention is to provide improved means for preventing damage to the flexible member which is wound and unwound on the reel of the actuating mechanism, which might be occasioned by winding the flexible member on the reel in the opposite direction from that in which it is normally wound.

Other objects of the present invention will more fully appear from the following detailed description taken in connection with the accom-' Figure 3 is an enlarged fragmentary sectional view through one side of the associated window frame, showing constructional details of the blind raising and lowering mechanism. v

Figure 4 is an enlarged section taken substantially on line IVIV of Figure 1; I

Figure '5 is an enlarged sectional view taken substantially on line.V-V of Figure 3;

Figure 6 is a side view of a modified form of raising and lowering mechanism, showing its as sociation with a slat guide member;

Figure 7 is a rear view of the same attached to a window frame; a

Figure 8 is a fragmentary sectional plan view of the same;

Figure 9 is a sectional view taken through the housing-of the raising and lowering mechanism showing the operative relationship of the instrumentalities therein; taken substantially on line 10 IXIX of Figure 7, the slat guide member being removed;

Figure 10 is a transverse sectional view through the same, taken substantially on line XX of Figure 9;

Figure 11 is a plan view of a standard blank .which may be utilized for forming right or left hand mountable housings for the raising and ings.

Figure 13 is a transverse sectional view showing the details of another modified'form of reel mechanism; and

Figure 14 is an enlarged fragmentary sectional view of the same, taken substantially on line XIVXIV of Figure 13, to show the details 0 its latching mechanism.

As shown on the drawings:

The numeral 6 indicates a window frame to.- which my improved blind is applied. It will be understood that the frame is provided with the usual sash but this has been omitted for convenience of illustration. Secured to one side of the frame is a guide r'ail'comprising a pair of strips 1, spaced apart to form a tape passage 8 and a facing strip 9. The latter strip is provided with a guideway preferably lined with .a metal channel bar l0. Secured to the other side of the 40 frame is a second guide rail II similar in all respects to the rail just described except that the tape passage 8 may, if desired, be omitted. Connecting the upper ends of the two guide rails is a rail ll having formed therein a tape passage I2.

\The tilt bar I3 is removably supported by a pair of hangers i3 and I4, the latter being provided with the usual gearing and operating cord l5 for controlling the position of the bar. These hangers may be of any usual and well-known construction and, therefore, need not be described any connection thereto. They are provided at each end with the usual trunnions 22 projecting into the channel bars ill. The fact that the slats are not attached to the tapes permits of their quick and easy removal and also permits relative movement between the slats and the tapes which, together with the clamping of the tapes along the center line of the tilt bar, insures light tight .closure of the slats when the tilt bar is moved in the rail H to the opposite side of the frame and over a roller 21. The tape 25 passes upwardly through the channel "I in the strip 9 and also passes over the roller 21. The two tapes 24 and 25, tfter passing over the roller 21, are connected to a tape 28 (which may be a continuation of one of them). Tape 28 passes downwardly through the tape passage 8 to a roller 29,, being twisted through an angle of 90 degrees during its passage. After passing around the roller 29, the tape enters a casing 38 and is securedrto a winding drum or reel 3| mounted therein.

In its passage to roller 29 the tape 28 passes behind a clutch block 32 having pins 33 movable in inclined slots 34 in a bracket 35 secured in the tape passage 8. A spring 36 normally forces the block upwardly to clamp the tape. The tape is thus free to move downwardly but is locked against upward movement until the block is released. Bearing upon the upper end of the block is one end of a bell-crank lever 31, the other end of which is pivoted to the stem of a push-button 38, normally held in forward position by a. coil spring 39 surrounding its stem. -The drum 3| rotates freely on a shaft 48 provided at its outer end with a handle 4| and having non-rotatably secured thereto-a block 42 carrying a pivoted pawl 43 adapted to engage with internal ratchet teeth 44 on the drum.

The operation of the form of the invention just described is as follows:

To raise the blind the handle 4| is rotated in a clockwise direction. This causes the pawl 43 to engage with the ratchet teeth 44 and rotate the drum 3|. The tape 28 is then wound on the drum, thus drawing up the tapes 24 and 25. This elevates the lift bar 23 which carries with it the slats 28. When the blind is raised to the desired position the handle is released and will return to neutral position, as shown in the drawings. The action of the clutch block 32 on the tape 28 prevents the return of the lift bar and slats to lowered position until the tape is released by pressure on the push-button 38. The use of the ratchet is to prevent the operator from rotating the drum in a counterclockwise direction which would result in slack in the tape 28 and consequent kinking or buckling of the tape,

he modified form of the raising and lowering mechanism as illustrated in Figures 6 to 12 will now be described:

In its broad concept, this form of the invention operates upon the same broad principles as the previously described form of the invention.

As shown in Figure 6, this form of the invention includes a housing construction generally indicated at 45, which is adapted to be formed from a preformed blank n a manner which will be subsequentlydescribed. This housing is arranged to suitably support the associated instrumentalities of the mechanism, and is also arranged to be associated with afabricated guide member 46 which may be secured in any suitable manner to the window frame.

Asshown, the guide 46' comprises a web portion 41 having a V-shaped trough 48 along one edge defined by diverging members 49 and 58. Along the opposite edge of the guide, the web is formed to define a T-shaped foot 5| which may be provided with suitable holes therethrough by means of which the guidemay be secured to the window frame so as to extend vertically therealong. The V-shaped trough 48 is arranged to receive the slat trunnions therein for vertical movement in the same manneras the trunnions 22 are received into the channel bar guide "I is previously described.

The housing is a box-like structure comprising a main plate portion 52, front and rear walls 53 and 54 respectively and a side wall 55' 'which is in spaced relation and parallel to the main plate 52. The upper and lower edges of the front and rear walls are inclined and arranged to receive thereintop and bottom coverplates 56 and 51 respectively which are similarly formed to permit their being interchanged.

Mounted in aligned openings 58 and 59 of the side wall 55 and base plate 52 respectively of the housing is a shaft 68 which is. held against rotative movement in any suitable manner. In the present instance this shaft is provided at one end with'a head BI and is riveted or peened over at its other end as shown at 62.

Rotatably mounted on the shaft 68 is a winding reel 63 which is formed with a circumferentially extending channel or groove 64which is adapted to have wound thereon in superposed layers the tape 28.

The reel 63' is maintained in spaced operative relationship relative to the wall 52 by means 'of a collar spacer 65 which is disposed between the reel and the wall 52 surrounding the shaft 68. Also, the reel is secured for simultaneous rotative movement to a helical worm gear 66.

Meshing with the worm gear 56 is a triple thread worm 61 which is shaft 68 extending at right angles relative to shaft 68 and having its ends rotatably supported in the front and rear walls 53 and 54 of the housing. Oneend of this shaft projects past the front wall of the housing and is formed with a polygonal end 69 adapted to receive an operating handle by means of which the shaft may be rotated.

From experience, it has been found that with i" 3 ordinary type of worm and worm wheel drive, for the purpose described herein, they do not give a practical operating speed, whenthe pitch of the worm and gear are so selected as to prevent reverse drive of the mechanism due to the weight of the blind. In order to overcome this difficulty, the present invention resorts to the novel expedient of providing a worm and worm gear drive in which the angle of warm lead is greater than the helix angle of the worm gear." Such a design is contrary to good gear design and in fact results in an inefiicient power transmitting arrangement. This arrangment, due to the fact that it is operated at low speed, sacrifices some of the advantages of eificient operation, but does result in effecting the desirable advantage of setting up sufficient friction between the meshing teeth of the'worm and the teeth of the worm fixedly secured to a is cut out to form an opening III, as shown in Figure '7 in the web portion 41, and foot portion 5| of the guide strip of suflicient size to enable the insertion of the base plate 52 of the housing into the opening beneath the guide until the rear wall 54 of the housing abuts the guide member.

In this position, the reel 63 projects past the web portion 41 of the guide, as shown in Figure 8 suificiently to bring the strip 28 along the rear side of web 41. The strip 28 is connected at its v uppermost end to flexible connections corresponding to the two tapes 24 and 25 as previously described, except that in the present instance it is desirable that these flexible connections be small cables rather than strips. These cables will be carried downwardly through the V-shaped trough of the guide and connected to the lifting bar as in the previously described arrangement.

It has been found desirable when the lifting bar has been lowered to its lower limit to provide means for preventing further movement of the reel 63 in a'lowering direction.- This is accomplished by a novel latch arrangement which is controlled by the flexible connection strip T28. It will be obvious that if some means were not 'provided, the reel could be continued in its lowering movement and the strip 28 would be wound on the reel in the opposite direction with the result that it would become kinked and otherwise damaged.

In order to guard against such contingency, a latch member]! is pivotally supported at one end of a pivot stud 12 which is anchored to the base plate of the housing. The free end of the latch member projects into the channel 64 on the reel and is provided with a spring I3 which normally tends to rotate the latch in a clockwise direction about its pivot as viewed in Figure 9.

The base of the channel 64 is provided with an opening 14 which is adapted to receive the end of the latch arm therein, when there is no strip 28 wound on the reel. Thus, when the reel is being rotated in a counterclockwise direc tion as shown in Figure 9, which is the direction for lowering the blind, and the tape has been completely unwound, the latch passes into the opening 14 and prevents further movement of the reel in lowering direction. Of course, with this arrangement the -flexible connection to the lift bar should .be of proper length to assure that the tape 28 is unwound when the lift bar reaches the bottom of the window.

Although the latch II will prevent further lowering movement under these conditions of the reel 63, the reel is free to be moved'in the opposite or raising direction. As the reel is thus moved in raising direction, the tape 28 will be wound on the reel and since this tape covers the opening 14, the tape will prevent entrance of the latch into the opening during raising movement of the blind.

Referring to Figure 11, the preformed blank from which the housing is fabricated is shown. The various wall sections of the housing are integrally formed and provided with openings for receiving the shafts and 68.. The base plate section contains the opening 59 and also an opening 15 which may be utilized for mounting the pivot 12 of the latching arm H. In addition screw holes 16 are also provided in the base plate section. The front and end wall sections 53 and 54 are provided with openings 11 and 18 which are adapted in the finished housing for receiving the ends of shaft 88. Likewise, the side wall section 55 is provided with openings 58.

This blank maybe cut to the shape shown and provided with the various openings to form a standard preformed blank. This blank is adapted to be deformed into a housing suitable for right or left hand mounting simply-by bending the various sections in appropriate direction.

It is desirable to provide the base plate with longitudinally extending corrugations as shown at 19, and these corrugations may be stamped or otherwise formed in the base plate portion, the material being upset in proper direction depending upon whether the blank is to form a right or left hand housing.

With the blank as just described, it will not make any difference whether it is formed into a right orleft hand housing. In either case, the

apertures 58 and 59 will be properly aligned as will also the apertures 11 and 18.

,The rear wall section 54 is provided with diverging leg portions 80 and 8| having deflectible ends 82 and 83 to provide feet for welding or otherwise securing these leg portions to the baseplate 52, when the housing is'completely formed. These leg portions provide a suitable space so that the reel 63 may project from the housing may be, though not necessarily constructed from a preformed blank as described above.

The winding reel is mounted on a shaft 85' which is rotatably mounted in the housing walls. This shaft may be extended at one end to integrally form an operating handle 86, or if desired, this handle may be separately formed and adapted in any suitable manner for removably securing to the shaft.

Instead of providing similar end flanges on the winding reel, one end flange ofthe reel is defined by a latch wheel 81 having a plurality of teeth 88 arranged around 'its circumference. These teeth are cooperatively associated with a tooth 89 car"- ried by a latch member 90, this member being supported for raising and lowering guided movements on spaced guide pins 9| and 92. The pins are each anchored at one end in the adjacent wall of the housing and respectively project into guide slots 83 and 94. The latch member is therefore free to move upwardly and downwardly to move the tooth 89 out of and into meshing relation with the teeth on the latch wheel, the latch member being actuated downwardly by the action of gravity thereon.

The teeth 88 are correspondingly each provided with a curved abutment edge on one side as shown at 85, this edge being arranged to interfittingly engage with a mating surface 86 on the tooth 89, when the latch member is in lowered or latching position.

The other side of each of the teeth 88 is formed the curved edge 85. The edges 91 are arranged the tooth 89 is moved out of its cooperative relation with the teeth on the latch wheel.

With the latch member moved to. unlatched position, the reel is then free to be moved in either direction, and so long as the reel is operated at a relatively fast speed the latch member will be prevented bythe teeth from moving to latching position. However, as soon as movement of the reel is terminated the latch member under the action of gravity is moved to latching position wherein the tooth 89 provides a stop for preventing movement of the latch wheel and consequently the winding reel in a counterclockwise direction.

In using this form of reel mechanism, the flexible tape connecting the reel to the lifting bar of the blind is wound-on the reel in such direction that the weight of the blind tends to cause the reel and latching wheel to move in a counterclockwise direction; as shown in lzgure 14.

By the use of thismechanism, the blind may readily and easily be moved, 'rom one position of adjustment to another. Ii he blind is to be raised, the crank or handle is merely moved in the raising direction until the blind is at the desired height, and as soon as the crank movement is stopped, the latch will operate to positively hold the blind. To lower the blind, the

F crank is initially moved in a raising direction to cause the latch to be released, whereupon the crank is actuated in the other direction to lower the blind to the desired position. As soon as the crank movement is stopped, the latch again operates to positively hold the blind at its new position'of adjustment.

From the foregoing description, it will be apparent that the present invention provides improved means for raising. and lowering a blind; which embodies novel means for automatically maintaining the blind in adjusted position and at the same time enables it to be readily and easily raised and lowered to other positions of adjustment; which embodies a novel irreversible worm gear drive; which is provided with novel 1 means for preventing damage to the flexible member which is wound on the winding reel, which might be occasioned by winding the flexible member on the reel in the opposite direction; and in which the housing for the raising and lowering mechanism is fabricated for right or left mounting as desired from a standard preformed blank.

It is of course to be understood that although I have described in detail several embodiments of my invention, the invention is not to be thus limited but only insofar as defined by the scope and spirit of the appended claims.

I claim as my invention:

1. In a Venetian blind construction including a. plurality of slats supported for raising and lowering movements; means including a manually actuatable winding drum mechanism for raising said slats, and means for frictionally opposing lowering movement of said slats.

2. In a device of the character described including a lifting bar; means operable to adjustably raise and lower said lift bar, said means including frictionally engaged elements automatically operable to maintain the lift bar in adjusted position. v

3. A device of the class described including a lift bar; actuating means for moving said lift bar in one direction, automatic clutch mechanism for preventing movement of the lift bar in the other direction at any ,point thefirst movement ceases, and means for releasing the clutch mechanism.

4. A device of the class described including a lift bar; actuating means for moving said lift bar in one direction, said means including a flexible connection, a winding drum for said connection, automatic clutch mechanism operating on said connection to prevent movement of the lift bar in the other direction, and means for releasing said clutch. mechanism.

5. A device of the class described including a lift bar; actuating means for moving said lift bar in one direction, said means including a flexible connection, a winding drum for said connection, manually operated means for actuating said drum, and a clutch for said connection.

A connection; a winding drum for said return connection, and a clutch operating on said return connection to prevent its movement in one direction.

8. A device of the class described including guideways, a lift bar, a pair of flexible connections attached to the ends of said lift bar and extending through said guideways, and a return flexible connection attached to said first named connection; a winding drumfor said return connection, manually operated means including a ratchet for actuating said drum, and a clutch operating on the return connection to prevent its movement in one direction.

9. In a device of the character described having a lift bar; means for raising and lowering said' lift bar, said means comprising a rotatably mounted winding drum adapted to have a flexible connection between said drum and lift bar wound thereon, and latch means for opposing movement of said drum in a direction to lower said lift bar, when the lift bar has been lowered a predetermined amount.

10. In a device of the character described in cluding a lift bar supported for raising and lowering movements; a winding drum adapted to have a flexible connection between said drum and lift bar wound and unwound thereon to raise and lower said lift bar, a latch member associated with said drum for opposing movement of the drum in a lowering direction, upon lowering movement of the lift bar to a predetermined position, the movement of the latch to latching position being governed by said flexible connection.

11. In a device of the character described including a lift bar supported for raising and lowering movement between upper and lower limits respectively; a winding drum adapted to have a flexible connection associated with the life bar wound thereon, means for latching the winding drum against movement in one direction, movement of said latch to latched and unlatched positions relativeto the drum being controlled by said flexible connection.

12. In a device of the character described including a lift bar supported for raising and lowering movements between upper and lower limits respectively; a winding drum adapted to have a flexible connection associated with the lift bar wound thereon in one direction, and means opposing operation of said drum to wind the flexible connection thereon in an opposite direction.

13. In a Venetian blind having a plurality of slats supported for raising and lowering movements; a .winding reel adapted to have a flexible connection wound and unwound thereon to raise and lower said slats, and an irreversible worm and gear drive for actuating said reel.

14. In a Venetianblind having a plurality of slats supported for raising and lowering movements; a winding reel adapted to. have a-flexible connection wound and unwound thereon to raise and lower the slats, and a worm and gear drive for actuating said reel, and means for frictionally opposing reverse drive of said worm and gear.

15. In a Venetian blind having a plurality of slats supported for raising and lowering movements; a winding reel adapted to have a flexible connection wound and unwound thereon to raise and lower said slats, and a worm and helical gear drive for actuating said reel in which the angle of worm lead difiers from the helix angle of the gear.

16. In a Venetian blind having a plurality of slats supported for raising and lowering move- 'ments; a winding reel adapted to have a flexible connection wound and unwound thereon to raise and lower said slats, and a worm and helical gear drive for actuating said reel in which the angle of worm lead is greater than the helix angle of the worm gear.

17. In a device of the class described having a lift bar; a winding reed connected to said lift bar whereby it may be raised and lowered, and means for automatically'latching the winding reel against movement in a lowering direction, and means for releasing said latch.

18. In a device of the class described having a lift bar; a winding reel connected to said lift bar whereby it may be raised and lowered, and means for automatically latching the winding reel against movement in a lowering direction, and means responsive to a reverse movement of said reel for releasing said latch to enable movement of the reel in a lowering direction.

19. In a device of the character described including a bar supported for raising and lowering movement; actuating "means operable in opposite directions to move said bar, and latch means normally tending to move to a position latching the actuating means against movement in a directionto lower the bar, said latch means being actuatable to unlatched position in response to an initial movement of the actuating means in a direction to raise the bar.

20. In a device of the character described including a bar supported for raising and lowering movements; actuating means movable in opposite directions to raise and lower the bar, and latch means retained .in unlatched position during relatively fast movements of the actuating means, said latch means being automatically actuated to a position latching the actuating means against movement in one direction, when the movement of the actuating means is relatively slow or it is stopped.

21. In a device of the character described including a bar supported for raising and lowering movements; a winding reel connected to said bar, a toothed latching wheel movable with said reel, and a latch member normally forming a stop opposing movement of the wheel in one direction but permitting movement in the opposite direction, said teeth being so shaped as to actuated the latch to unlatched position during said latter movement and thereafter retain the latch in unlatched position as long as the wheel is moved with a relatively fast speed in either direction.

FRED E. LAWSON. 

